[PATCH v1] LoongArch: add i2c clocks and clock-div parameter parsing.

[Hongliang Wang]

On 3A/7A/2K platform, i2c ref clocks and clock divisor maybe
different, through firmware parameter passing, "clocks" and
"clock-div" are used to describe i2c ref clocks and divisor.

Signed-off-by: Hongliang Wang <wanghongliang@xxxxxxxxxxx>
---
 drivers/i2c/busses/i2c-ls2x.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-ls2x.c b/drivers/i2c/busses/i2c-ls2x.c
index b475dd27b7af..562bf32a9d6c 100644
--- a/drivers/i2c/busses/i2c-ls2x.c
+++ b/drivers/i2c/busses/i2c-ls2x.c
@@ -96,6 +96,8 @@ static irqreturn_t ls2x_i2c_isr(int this_irq, void *dev_id)
 static void ls2x_i2c_adjust_bus_speed(struct ls2x_i2c_priv *priv)
 {
 	u16 val;
+	u32 pclk;
+	u32 div;
 	struct i2c_timings *t = &priv->i2c_t;
 	struct device *dev = priv->adapter.dev.parent;
 	u32 acpi_speed = i2c_acpi_find_bus_speed(dev);
@@ -107,12 +109,16 @@ static void ls2x_i2c_adjust_bus_speed(struct ls2x_i2c_priv *priv)
 	else
 		t->bus_freq_hz = LS2X_I2C_FREQ_STD;
 
+	if (!device_property_read_u32(dev, "clocks", &pclk) &&
+		!device_property_read_u32(dev, "clock-div", &div) && div != 0)
+		val = (pclk * 10) / (div * t->bus_freq_hz) - 1;
+	else
+		val = LS2X_I2C_PCLK_FREQ / (5 * t->bus_freq_hz) - 1;
 	/*
 	 * According to the chip manual, we can only access the registers as bytes,
 	 * otherwise the high bits will be truncated.
 	 * So set the I2C frequency with a sequential writeb() instead of writew().
 	 */
-	val = LS2X_I2C_PCLK_FREQ / (5 * t->bus_freq_hz) - 1;
 	writeb(FIELD_GET(GENMASK(7, 0), val), priv->base + I2C_LS2X_PRER_LO);
 	writeb(FIELD_GET(GENMASK(15, 8), val), priv->base + I2C_LS2X_PRER_HI);
 }
-- 
2.47.2